During the first year of the proposal Bag Cells were dissected from the rest of Aplsia ganglia and the egg-laying hormones from these cells were isolated by a combination of gel filtration and ion exchange chromatography. The biologically active egg-laying peptides were chemically characterized by molecular size, isoelectric point and amino acid analysis. Studies directed toward analyzing the incorporation of amino acids into the Bag Cell peptides were also performed. These results indicate that incorporation of amino acid into the Bag Cell is in some way connected to alterations in the Aplysia cell membrane which is very lipid-rich. Pulse-chase experiments with 3H-leucine were performed in the presence and absence of colchicine to help define precursor-product relationships within the Bag Cell. These results suggest that the product of 3,000 molecular weight may arise from an intermediate of 29,000 or a precursor of 65,000 daltons. Effort is now being made to accumulate sufficient material for amino acid sequence analysis. These egg-laying peptides in Aplysia will also be studied in the mammalian system for effects in capacitation (see letter of collaboration with Lourens Zanveld, of the Department of Physiology and Biophysics, University of Illinois Medical Center).